The problem with oxidatively coloring or blonding hair is that the keratin fibers may be damaged by the aggressive substances. In particular, the natural hydrophobicity of the keratin fiber is reduced since the coloring or lightening agents initially have to render the hair penetrable so as to develop their effect. The water-repelling action, however, provides natural protection of the hair, and additionally is closely associated with parameters desired by the consumer, such as shine, suppleness, feel, and “laying” of the hair.
So as to overcome the aforementioned drawbacks, what are known as pre-treatment agents are available on the market, which are to protect the hair from aggressive influence. However, these often weigh the hair down or impair the success of the subsequent lightening process or coloration of the hair, and in particular the washing fastness of the color may be adversely affected by the pre-treatment agent. In addition, numerous post-treatment agents are known, which are used to attempt to repair damage caused to the hair during the oxidative coloring treatment. All of these methods, however, require a multi-stage application process, involving an application of a further hair treatment agent prior to or after coloring. This is frequently perceived as inconvenient by the consumer, since the oxidative coloring treatment itself already involves multiple work steps and an exposure time of as much as 60 minutes, making the process very complex.
It was the object of the present invention to provide an agent and a method for oxidatively coloring hair using a treatment that protects hair, which overcomes the aforementioned drawbacks, without negatively influencing the color result of the oxidative coloring treatment. In particular, a coloring agent and a method were to be provided, in which the hair is not weighed down and which cause preferably little damage to the hair. Furthermore, the achieved protection of the hair should command as little time as possible and preferably take place directly together with the coloring step.
The use of permanently cationic polymers in hair care is state of the art. These are widely used in shampoos, and in particular in conditioners, so as to develop nourishing effects there. Patent application CA 2066226 A, for example, discloses hair conditioners comprising amphoteric polymers composed of cationic and anionic units, wherein the cationic units are present in excess in relation to the anionic units, and the polymers are thus, in sum, permanently cationic.
It was now found that oxidative coloring agents that, in addition to typical components such as water, ammonium hydroxide and/or monoethanolamine serving as the alkalizing agent, and a peroxide compound such as hydrogen peroxide, comprise a special combination composed of a select polymer, a permanently cationic polymer and at least one amino acid, result in considerably improved protection of the hair during the oxidative coloring treatment, without impairing the results of the oxidative coloring treatment. Surprisingly, it was found that the combination according to the invention, composed of a select polymer, a permanently cationic polymer and at least one amino acid, protects the hair during coloring and/or lightening from damage caused by the high pH of the agent and by the oxidizing agent. This was able to be established, among other things, in that less hair breakage occurred during subsequent combing, and the hair lost less elasticity, as demonstrated by stress-strain measurements, than after the application of coloring and blonding agents not according to the invention.
Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with this background of the invention.